a) Field of the Invention
The present invention relates to a disk music box which plays reeds by rotating a plurality of pinwheels at a plurality of engagement portions arranged on a disk so that they play a music.
b) Description of the Related Art
A popular disk music box drive a disk which is formed with an engagement portion (e.g. a plurality of holes or convexities) which plays music so the engagement portion plays reeds while a plurality of pinwheels are rotated. A spacer is arranged in each of the pinwheels in the music box for maintaining a predetermined space therebetween. However, putting them in the music box is an elaborate work. As one of the solution for the problem, a disk music box is disclosed in Japanese Utility Model H7-34464. The pinwheels and pin shaft are supported by partitions, which forms a plurality of spaces in the shaft direction, and a housing formed integral with a bearing, which supports the pin shaft. In the housing, projections control rotation of pinwheels by being engaged/disengaged with the same.
To maintain the engaged state of the disk and pinwheels constant, generally, force from a disk is urged in the direction farther from pinwheels by bending the circumference sides of pinwheels of the disk upward via a guiding member. At the same time, a flat portion is formed at the portion opposite the pinwheels, onto which a rollers formed on the arm are pressed to transmit force in the direction the disk becomes closer to the pinwheels. This configuration is too complex to make adjustment; this is a problem.
In the disk music box disclosed in Japanese laid open patent H9-97054, a plurality of press rollers which contact the disk is rotatably formed on the arm such that the press rollers are arranged opposite the pinwheels to guide the disk. In other words, the arm is rotatably supported by a shaft which is fixed onto a pillar formed on the music box frame. By having the lever formed on the tip of the frame being engaged with the center shaft on which the disk is attached, a plurality of rollers are aligned and press the disk. To remove the disk from the disk music box, the engagement between the center shaft and the lever is released and the arm is rotated such that it retreats from the disk. Then, the disk is taken out from the center shaft.
A music box of conventional technology is supported by the bearing surface formed on the housing which holds the pinwheels shaft, which is made of a resin. Therefore, the rigidity of the housing or mounting portion of the pin shaft have poor rigidity. If the housing or pin shaft mounting portion have poor rigidity, the pin shaft will retreat when the pinwheels play the reeds; this creates dull sound, which is a poor sound quality. Especially, when a plurality of pinwheels play a plurality of reeds, a heavy load is placed on the pin shaft, making the sound significantly poor. An idea to improve the sound quality is to form the housing body integral with the frame. However, the pinwheels are thin because they are formed to be as many as the number of reeds. As a result, narrow partitions must be machined; and this machining is difficult.
The movement control projections play a melody when the pinwheels rotate due to engagement with the projections. The contacting sound (played sound) turns into noise, degrading sound quality. The guiding member which curves the disk is formed on a frame, the disk loading space must be provided on the frame; this makes it difficult to reduce the size of the music box. If a guiding member and a disk are together made of a metallic material, both abrade and wear out as the disk rotates; this makes it difficult to position the disk appropriately and affects the durability of the disk.
When a motor is the disk drive source, a larger load increases power consumption; this decreases the usable life time of the disk music box.
Also, because the arm is simply rotatably supported by the shaft of the pillar, the arm motion cannot be stopped in the middle of rotation. This makes it difficult to remove/place the disk. When the music box operator stops rotating the arm, the arm may continue rotating by its own weight, contacting the housing or disk, damaging the arm, disk, or housing.